It has previously been reported that when venom immunotherapy is discontinued after 5 years or more, the risk of a sting reaction remains less than 10% in the first few years after stopping treatment. Some investigators have studied discontinuation of therapy after only 3 years, but have suggested restrictions such as younger patients, milder reactions, and negative sting challenge during therapy or negative RAST. The results of this study will show whether patients can safely stop therapy after only 3 years instead of our current recommendation of 5-6 years, and whether the risk of reaction remains acceptably low in the 10 years after stopping therapy. Also, we will determine whether there is a lower risk in those patients with a less severe history of reaction before treatment or in those who have developed negative skin tests, and/or RAST.